RE: Covering Power of Pinholes

Hello Joe,

I would suggest, you look at www.mrpinhole.com
<http://www.mrpinhole.com/> for camera design, pinhole sizes and
coverages etc.

Of course, there are very experienced pinholers on the list to help too.

achal

-----Original Message-----
From: pinhole-discussion-admin@pinhole.com
[mailto:pinhole-discussion-admin@pinhole.com] On Behalf Of Joe Tait
Sent: Thursday, May 30, 2002 8:50 PM
To: pinhole-discussion@pinhole.com
Subject: [pinhole-discussion] Covering Power of Pinholes

Hello!

New to the list and this is my first post.

A little background.....

I have been doing photography for 6 years, and currently shoot 4"x5" w/
a Cambo Legend monorail and 6x7 with a Koni Rapid 200. Most of my
experience has been with conventional silver printing, but I have tried
cyanotype & gum bichromate in the last 6 months, and am going to plunge
forward into various alt processes as I can.

I really want to try pinhole next, and want larger negatives for contact
printing. I've found some interesting info on the web and will build my
own camera & pinhole very soon. One thing that I am confused about is
determining how much covering power a given pinhole has. Is it just
relative to the distance of the pinhole to film/pinhole dia., which then
determines the "focal length"? Forgive me, I struggle with comprehending
even the most basic concepts of optics generally, and am no better with
pinhole.

I'd like to try say an 11"x14" format, or perhaps a panoramic 8"x16".
The wide-angle possibilities (both the really wide & moderate) are in
my sights first and I like distortion, but not to the point of monotony.
I am looking to use sheet Lith film developed in dilute developer, or
pyro; and will be making my own film holders and back to be able to do
multiple exposures.

Could someone enlighten me how to figure out the proper pinhole size &
lens-to-film distance for the aforementioned formats? I understand that
a curved film plane is employed to compensate for light fall-off. Is the
optimum curve determined by experience, or are there known combinations?

I haven't found any books that focus on specifics. Eric Renner's book
apparently focuses on the history more than construction, which is the
opposite of what I want to learn first. Perhaps someone could recommend
more literature because the web only seems to offer an overview of
pinhole.

Lastly, Larry Bullis' excellent article on pinhole construction
mentioned using silver sheeting & a microscope to make pinholes. I'd
actually like to try both of these methods. Does anyone work in this
way? Where do you get the silver sheeting and what kind of microscope do
you use? Precision pinholes seem to really effect the resolution, quite
appropriate for certain shots (although the softness is perfect for
others).

Thanks.

-Joe
Received on Fri May 31 03:16:03 2002